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Fangasm aside, that was quite the informative trailer. I noticed everything everyone else mentioned, so I'm not going to post that, but I did notice more subtle clues. At least, I think they're clues.
First, I noticed that the sword wasn't the Master Sword. (Of course it very well could be.) BUT he had that sword throughout the whole trailer, even when the sword spirit icon appeared. So I wonder how the spirit will be implemented into the plot, and where we find the Master Sword, for that matter.
Second, the golden Aztec statue had a similar aesthetic to the golden door with the dragon puzzle key, leading me to believe that they are in the same location. Plus the pale character is sitting on top of that statue. Here's how I picture it: The dragon key leads to the statue room, where the pale guy either talks to you before or after a fight with the statue, then disappears. It makes sense, since I know villains (Zant specifically,) typically appear before the boss in a seemingly semi random dungeon, and if you notice, there's perpetual dark energy above the statue's head, right where the pale guy was.
Before, many people thought the Hyrulian bird crest and Triforce behind the title was a placeholder, but since those crests have received a redesign in the new trailer to look more old and archaic, I believe we will see more info on that.
The mechanical areas look quite interesting too. Something about them makes me think they're underground. By the way, the item at 21 looks like a deformed hookshot to me.